DESCRIPTION: Advances in imaging, genetics, and sequencing have made it possible to identify, track, and manipulate molecules involved in many different cellular processes in living cells. But are our models of these processes complete and correct at the molecular level? And can we understand mechanistically why these processes fail and what might be required to repair them? This is especially a challenge for processes that involve membrane proteins, such as those that mediate interactions with extracellular signals. Even though membrane proteins comprise ~30% of human genes and are important targets for drugs, the techniques available for characterizing and manipulating them are severely limited. What is needed to answer basic and applied questions about membrane protein function is a technology for re-building cell-like systems from the bottom up that recapitulates the spatial organization, confinement, and dynamic properties of living cells. This project will develop a new instrument capable of creating membrane encapsulations with oriented membrane proteins, offering a new experimental platform for answering questions about how information is transmitted across membranes. By encapsulating complex mixtures of proteins, DNA, and other biomolecules inside bilayer membrane vesicles with high throughput and high yield, the proposed instrument will address a fundamental obstacle in our understanding of how membrane proteins, beginning with EGFR and GPCRs, organize and respond to stimuli.